The objectives of this project are to assess the importance of local factors on alveolar bone resorption and to determine whether agents absorbed locally through intact or injured gingiva as in periodontal disease, contribute to generalized osteoporosis. The animal model is the 22 day old New Zealand White rabbit. The sulci of the 1st mandibular incisors are used for the atraumatic instillation of the test substance or for the local injection of the agent. Since it was found that the intact gingiva is an effective barrier to heparin while heparin can exert systemic on bone resorption in metaphyseal as well as alveolar bone if injected into the gingiva, the effects of repeated local treatment will be studied. In addition agents known to inhibit bone resorption will be studied in the attempt to prevent or reverse the effects of local agents.